School is in session and Orlando Bloom, Jay Chou, Kate Hudson, Jessica Chastain and Cara Delevingne are your classmates

We're calling it: Katy Perry threw the birthday/Halloween party of the year. The singer, who turned 32 on 25 October, threw a '50s high school-themed party where she presided as principal (that's Principal Hudson to you) of Hudson High.

There was a classroom-themed photobooth, a giant Twister board, a pie-eating contest that Cara took part in, a hula hoop competition, and performances by impersonators dressed as Marilyn Monroe, Elvis Presley and The Supremes. Nothing beats actually having been at the party, but we mortals just have to make do with what's on social media (and that's already impressive enough).